SIRT1 Modulating Compounds from High-Throughput Screening as Anti-Inflammatory and Insulin-Sensitizing Agents (original) (raw)
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How much successful are the medicinal chemists in modulation of SIRT1: A critical review
European journal of medicinal chemistry, 2016
Silent information regulator two homologue one (SIRT1) is the most widely studied member of the sirtuin family related to histone deacetylases class III super-family using nicotinamide adenine dinucleotide (NAD(+)) as its cofactor. It is located in the nucleus but also modulates the targets in cytoplasm and mainly acts as transacetylase rather than deacetylase. SIRT1 specifically cleaves the nicotinamide ribosyl bond of NAD(+) and transfers the acetyl group from proteins to their co-substrate through an ADP- ribose-peptidyl imidate intermediate. It has been indicated that SIRT1 and its histone as well as non histone targets are involved in a wide range of biological courses including metabolic diseases, age related diseases, viral infection, inflammation, tumor-cell growth and metastasis. Modulation of SIRT1 expression may present a new insight in the discovery of a number of therapeutics. This review summarizes studies about SIRT1 and mainly focuses on the various modulators of SIR...
Small molecule activators of SIRT1 as therapeutics for the treatment of type 2 diabetes
Nature, 2007
Calorie restriction extends lifespan and produces a metabolic profile desirable for treating diseases of ageing such as type 2 diabetes 1,2 . SIRT1, an NAD + -dependent deacetylase, is a principal modulator of pathways downstream of calorie restriction that produce beneficial effects on glucose homeostasis and insulin sensitivity 3-9 . Resveratrol, a polyphenolic SIRT1 activator, mimics the antiageing effects of calorie restriction in lower organisms and in mice fed a high-fat diet ameliorates insulin resistance, increases mitochondrial content, and prolongs survival 10-14 . Here we describe the identification and characterization of small molecule activators of SIRT1 that are structurally unrelated to, and 1,000-fold more potent than, resveratrol. These compounds bind to the SIRT1 enzyme-peptide substrate complex at an allosteric site amino-terminal to the catalytic domain and lower the Michaelis constant for acetylated substrates. In diet-induced obese and genetically obese mice, these compounds improve insulin sensitivity, lower plasma glucose, and increase mitochondrial capacity. In Zucker fa/fa rats, hyperinsulinaemic-euglycaemic clamp studies demonstrate that SIRT1 activators improve whole-body glucose homeostasis and insulin sensitivity in adipose tissue, skeletal muscle and liver. Thus, SIRT1 activation is a promising new therapeutic approach for treating diseases of ageing such as type 2 diabetes.
PLoS ONE, 2012
Chronic inflammation is a major contributing factor in the pathogenesis of many age-associated diseases. One central protein that regulates inflammation is NF-kB, the activity of which is modulated by post-translational modifications as well as by association with co-activator and co-repressor proteins. SIRT1, an NAD + -dependent protein deacetylase, has been shown to suppress NF-kB signaling through deacetylation of the p65 subunit of NF-kB resulting in the reduction of the inflammatory responses mediated by this transcription factor. The role of SIRT1 in the regulation of NF-kB provides the necessary validation for the development of pharmacological strategies for activating SIRT1 as an approach for the development of a new class of anti-inflammatory therapeutics. We report herein the development of a quantitative assay to assess compound effects on acetylated p65 protein in the cell. We demonstrate that small molecule activators of SIRT1 (STACs) enhance deacetylation of cellular p65 protein, which results in the suppression of TNFa-induced NF-kB transcriptional activation and reduction of LPS-stimulated TNFa secretion in a SIRT1-dependent manner. In an acute mouse model of LPS-induced inflammation, the STAC SRTCX1003 decreased the production of the proinflammatory cytokines TNFa and IL-12. Our studies indicate that increasing SIRT1-mediated NF-kB deacetylation using small molecule activating compounds is a novel approach to the development of a new class of therapeutic anti-inflammatory agents. Citation: Yang H, Zhang W, Pan H, Feldser HG, Lainez E, et al. (2012) SIRT1 Activators Suppress Inflammatory Responses through Promotion of p65 Deacetylation and Inhibition of NF-kB Activity. PLoS ONE 7(9): e46364.
Synthesis and Assay of SIRT1-Activating Compounds
Methods in Enzymology, 2016
The NAD +-dependent deacetylase SIRT1 plays key roles in numerous cellular processes including DNA repair, gene transcription, cell differentiation, and metabolism. Over-expression of SIRT1 protects against a number of age-related diseases including diabetes, cancer, and Alzheimer's disease. Moreover, overexpression of SIRT1 in the murine brain extends lifespan. A number of small-molecule sirtuin-activating compounds (STACs) that increase SIRT1 activity in vitro and in cells have been developed. While the mechanism for how these compounds act on SIRT1 was once controversial, it is becoming increasingly clear that they directly interact with SIRT1 and enhance its activity through an allosteric mechanism. Here, we present detailed chemical syntheses for four STACs, each from a distinct structural class. Also, we provide a general protocol for purifying active SIRT1 enzyme and outline two complementary enzymatic assays for characterizing the effects of STACs and similar compounds on SIRT1 activity.
A potential treatment of nonalcoholic fatty liver disease with SIRT1 activators
2014
Sirtuins (SIRTs) are members of the silent information regulator-2 family and act as nicotinamide adenine dinucleotide (NAD+)-dependent histone/protein deacetylases. e de-acetylation of proteins and histones results in an up-or down-regulation of gene transcription and protein function. In recent years, the regulatory action of the deacetylation activity of SIRT1 has been shown to have a positive impact on the pathophysiological mechanisms of nonalcoholic fatty liver disease (NAFLD). Among the e ects of SIRT1 are: its healing activity on insulin sensitivity, thereby ameliorating glycemic regulation; its mimetic activity on calorie restriction; its antihyperlipidemic activity on lipid homeostasis via the liver, adipose tissues and skeletal muscles; its antiin ammatory activities; its protective e ects against cardiovascular events and endothelial dysfunction; its positive in uence on autophagy, apoptosis and cancer; and nally, its anti-aging activity. The current approach for the treatment of NAFLD involves the treatment of etiological factors and recommendation of lifestyle changes including more physical activity and a low-calorie diet. However, there is no speci c medical treatments for NAFLD. e therapeutic potential of SIRT1 activity in the treatment of NAFLD discovered in humans has been presented in this article. In this review, the potential e ects of SIRT1 activation on NAFLD-related pathophysiological mechanisms and on the treatment of NAFLD are discussed.
Analytical Biochemistry, 2009
Sirtuins are nicotinamide adenine dinucleotide (NAD + )-dependent deacetylases that catalyze the deacetylation of proteins such as histones and p53. A sensitive and convenient fluorometric assay for evaluating the SIRT1 enzymatic activity was developed here. Specifically, the remaining NAD + after the deacetylation was determined by converting NAD + to a highly fluorescent cyclized a-adduct compound. By this assay, we found that nicotinamide, Cu 2+ , and Zn 2+ antagonize the activity of SIRT1. Resveratrol stimulates the enzymatic activity specifically with 7-amino-4-methylcoumarin (AMC)-labeled acetylated peptide. Epigallocatechin galate (EGCG) inhibits SIRT1 activity with both AMC-labeled and unlabeled peptide. However, a combination of vitamin C with EGCG can reverse the inhibition of EGCG with the unlabeled peptide or stimulate the deacetylation of AMC-labeled peptide by SIRT1. The assay does not require any isotopic material and thus is biologically safe. It can be adapted to a 96-well microplate for highthroughput screening. Notably, the acetylated peptides with or without fluorescent labels may be used in the assay, which facilitates the substrate specificity study of SIRT1 activators or inhibitors in vitro.
SIRT1 Exerts Anti-Inflammatory Effects and Improves Insulin Sensitivity in Adipocytes
Molecular and Cellular Biology, 2009
SIRT1 is a prominent member of a family of NAD ؉ -dependent enzymes and affects a variety of cellular functions ranging from gene silencing, regulation of the cell cycle and apoptosis, to energy homeostasis. In mature adipocytes, SIRT1 triggers lipolysis and loss of fat content. However, the potential effects of SIRT1 on insulin signaling pathways are poorly understood. To assess this, we used RNA interference to knock down SIRT1 in 3T3-L1 adipocytes. SIRT1 depletion inhibited insulin-stimulated glucose uptake and GLUT4 translocation. This was accompanied by increased phosphorylation of JNK and serine phosphorylation of insulin receptor substrate 1 (IRS-1), along with inhibition of insulin signaling steps, such as tyrosine phosphorylation of IRS-1, and phosphorylation of Akt and ERK. In contrast, treatment of cells with specific small molecule SIRT1 activators led to an increase in glucose uptake and insulin signaling as well as a decrease in serine phosphorylation of IRS-1. Moreover, gene expression profiles showed that SIRT1 expression was inversely related to inflammatory gene expression. Finally, we show that treatment of 3T3-L1 adipocytes with a SIRT1 activator attenuated tumor necrosis factor alpha-induced insulin resistance. Taken together, these data indicate that SIRT1 is a positive regulator of insulin signaling at least partially through the anti-inflammatory actions in 3T3-L1 adipocytes.
SIRT1 Activation by Natural Phytochemicals: An Overview
2020
Sirtuins are class III histone deacetylases, whose enzymatic activity is dependent on NAD+ as a cofactor. Sirtuins are reported to modulate numerous activities by controlling gene expression, DNA repair, metabolism, oxidative stress response, mitochondrial function, and biogenesis. Deregulation of their expression and/or action may lead to tissue-specific degenerative events involved in the development of several human pathologies, including cancer, neurodegeneration, and cardiovascular disease. The most studied member of this class of enzymes is sirtuin 1 (SIRT1), whose expression is associated with increasing insulin sensitivity. SIRT1 has been implicated in both tumorigenic and anticancer processes, and is reported to regulate essential metabolic pathways, suggesting that its activation might be beneficial against disorders of the metabolism. Via regulation of p53 deacetylation and modulation of autophagy, SIRT1 is implicated in cellular response to caloric restriction and lifesp...
Interactomic and pharmacological insights on human Sirt-1
Sirtuin family, in humans as well as in all mammalia, is composed by seven different homologous proteins with NAD-dependent deacetylase/ADP-ribosyltransferase activity. Numerous studies have determined their cellular location and their biological functions. In particular, Sirt-1 is defined as a nuclear protein involved in the molecular mechanisms of inflammation and neurodegeneration through the de-acetylation of many different substrates (PGC-α, FOXOs, NFκB). However experimental data in mouse suggest both its cytoplasmatic presence and nucleo-cytoplasmic shuttling upon oxidative stress. Recently we have modeled the three-dimensional structure of human Sirt-1, and highlighted that it is composed by four different regions: N-terminal region, allosteric site, catalytic core and C-terminal region and underlined that the two terminal regions have high intrinsic disorder propensity. Since Sirt-1 is implicated in various diseases and cancers, many different papers report experimental studies related to its functional activators. The aim of this article is i) to present interactomic studies on human SIRT-1 to understand its most important functional relationships in the light of the gene-protein interactions that control major metabolic pathways and ii) to show how this protein binds some activator molecules in order to evidence structural determinants, physico-chemical features and those residues involved in the formation of complexes. It is believed that these data will be useful to synthesize new effectors through drug design approaches.